pnfsblock: xdr decode pnfs_block_layout4 (e9437cce) · Commits · e / devices / android_kernel_xiaomi_markw

fs/nfs/blocklayout/blocklayoutdev.c

+206 −2

Original line number	Diff line number	Diff line
		@@ -40,6 +40,19 @@

		#define NFSDBG_FACILITY NFSDBG_PNFS_LD

		static int decode_sector_number(__be32 *rp, sector_t sp)
		{
		uint64_t s;

		rp = xdr_decode_hyper(rp, &s);
		if (s & 0x1ff) {
		printk(KERN_WARNING "%s: sector not aligned\n", __func__);
		return -1;
		}
		*sp = s >> SECTOR_SHIFT;
		return 0;
		}

		/* Open a block_device by device number. */
		struct block_device *nfs4_blkdev_get(dev_t dev)
		{
		@@ -197,10 +210,201 @@ out:
		return rv;
		}

		/* Map deviceid returned by the server to constructed block_device */
		static struct block_device translate_devid(struct pnfs_layout_hdr lo,
		struct nfs4_deviceid *id)
		{
		struct block_device *rv = NULL;
		struct block_mount_id *mid;
		struct pnfs_block_dev *dev;

		dprintk("%s enter, lo=%p, id=%p\n", __func__, lo, id);
		mid = BLK_ID(lo);
		spin_lock(&mid->bm_lock);
		list_for_each_entry(dev, &mid->bm_devlist, bm_node) {
		if (memcmp(id->data, dev->bm_mdevid.data,
		NFS4_DEVICEID4_SIZE) == 0) {
		rv = dev->bm_mdev;
		goto out;
		}
		}
		out:
		spin_unlock(&mid->bm_lock);
		dprintk("%s returning %p\n", __func__, rv);
		return rv;
		}

		/* Tracks info needed to ensure extents in layout obey constraints of spec */
		struct layout_verification {
		u32 mode; /* R or RW */
		u64 start; /* Expected start of next non-COW extent */
		u64 inval; /* Start of INVAL coverage */
		u64 cowread; /* End of COW read coverage */
		};

		/* Verify the extent meets the layout requirements of the pnfs-block draft,
		* section 2.3.1.
		*/
		static int verify_extent(struct pnfs_block_extent *be,
		struct layout_verification *lv)
		{
		if (lv->mode == IOMODE_READ) {
		if (be->be_state == PNFS_BLOCK_READWRITE_DATA \|\|
		be->be_state == PNFS_BLOCK_INVALID_DATA)
		return -EIO;
		if (be->be_f_offset != lv->start)
		return -EIO;
		lv->start += be->be_length;
		return 0;
		}
		/* lv->mode == IOMODE_RW */
		if (be->be_state == PNFS_BLOCK_READWRITE_DATA) {
		if (be->be_f_offset != lv->start)
		return -EIO;
		if (lv->cowread > lv->start)
		return -EIO;
		lv->start += be->be_length;
		lv->inval = lv->start;
		return 0;
		} else if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
		if (be->be_f_offset != lv->start)
		return -EIO;
		lv->start += be->be_length;
		return 0;
		} else if (be->be_state == PNFS_BLOCK_READ_DATA) {
		if (be->be_f_offset > lv->start)
		return -EIO;
		if (be->be_f_offset < lv->inval)
		return -EIO;
		if (be->be_f_offset < lv->cowread)
		return -EIO;
		/* It looks like you might want to min this with lv->start,
		* but you really don't.
		*/
		lv->inval = lv->inval + be->be_length;
		lv->cowread = be->be_f_offset + be->be_length;
		return 0;
		} else
		return -EIO;
		}

		/* XDR decode pnfs_block_layout4 structure */
		int
		nfs4_blk_process_layoutget(struct pnfs_layout_hdr *lo,
		struct nfs4_layoutget_res *lgr, gfp_t gfp_flags)
		{
		/* STUB */
		return -EIO;
		struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
		int i, status = -EIO;
		uint32_t count;
		struct pnfs_block_extent be = NULL, save;
		struct xdr_stream stream;
		struct xdr_buf buf;
		struct page *scratch;
		__be32 *p;
		struct layout_verification lv = {
		.mode = lgr->range.iomode,
		.start = lgr->range.offset >> SECTOR_SHIFT,
		.inval = lgr->range.offset >> SECTOR_SHIFT,
		.cowread = lgr->range.offset >> SECTOR_SHIFT,
		};
		LIST_HEAD(extents);

		dprintk("---> %s\n", __func__);

		scratch = alloc_page(gfp_flags);
		if (!scratch)
		return -ENOMEM;

		xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
		xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);

		p = xdr_inline_decode(&stream, 4);
		if (unlikely(!p))
		goto out_err;

		count = be32_to_cpup(p++);

		dprintk("%s enter, number of extents %i\n", __func__, count);
		p = xdr_inline_decode(&stream, (28 + NFS4_DEVICEID4_SIZE) * count);
		if (unlikely(!p))
		goto out_err;

		/* Decode individual extents, putting them in temporary
		* staging area until whole layout is decoded to make error
		* recovery easier.
		*/
		for (i = 0; i < count; i++) {
		be = bl_alloc_extent();
		if (!be) {
		status = -ENOMEM;
		goto out_err;
		}
		memcpy(&be->be_devid, p, NFS4_DEVICEID4_SIZE);
		p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
		be->be_mdev = translate_devid(lo, &be->be_devid);
		if (!be->be_mdev)
		goto out_err;

		/* The next three values are read in as bytes,
		* but stored as 512-byte sector lengths
		*/
		if (decode_sector_number(&p, &be->be_f_offset) < 0)
		goto out_err;
		if (decode_sector_number(&p, &be->be_length) < 0)
		goto out_err;
		if (decode_sector_number(&p, &be->be_v_offset) < 0)
		goto out_err;
		be->be_state = be32_to_cpup(p++);
		if (be->be_state == PNFS_BLOCK_INVALID_DATA)
		be->be_inval = &bl->bl_inval;
		if (verify_extent(be, &lv)) {
		dprintk("%s verify failed\n", __func__);
		goto out_err;
		}
		list_add_tail(&be->be_node, &extents);
		}
		if (lgr->range.offset + lgr->range.length !=
		lv.start << SECTOR_SHIFT) {
		dprintk("%s Final length mismatch\n", __func__);
		be = NULL;
		goto out_err;
		}
		if (lv.start < lv.cowread) {
		dprintk("%s Final uncovered COW extent\n", __func__);
		be = NULL;
		goto out_err;
		}
		/* Extents decoded properly, now try to merge them in to
		* existing layout extents.
		*/
		spin_lock(&bl->bl_ext_lock);
		list_for_each_entry_safe(be, save, &extents, be_node) {
		list_del(&be->be_node);
		status = bl_add_merge_extent(bl, be);
		if (status) {
		spin_unlock(&bl->bl_ext_lock);
		/* This is a fairly catastrophic error, as the
		* entire layout extent lists are now corrupted.
		* We should have some way to distinguish this.
		*/
		be = NULL;
		goto out_err;
		}
		}
		spin_unlock(&bl->bl_ext_lock);
		status = 0;
		out:
		__free_page(scratch);
		dprintk("%s returns %i\n", __func__, status);
		return status;

		out_err:
		bl_put_extent(be);
		while (!list_empty(&extents)) {
		be = list_first_entry(&extents, struct pnfs_block_extent,
		be_node);
		list_del(&be->be_node);
		bl_put_extent(be);
		}
		goto out;
		}